Spark-plug



l. S. COYLE.

SPARK PLUG.

APPLICATION FILED JuNE26. |920.

Patented Aug. 2, 1921..

wrm/8858 Mfg@ G y TTURNEYS UNITED STAT-Es PATENT oFFlcE.

SPARK-PLUG.

Application led June 26, 1920. Serial No. 392,004.

T o @ZZ 'whom t may concern.'

Be it known that I, J AMES S. CoYLn, a citizen of the United States, and a resident oi St.` Louis, in the State of Missour,\have invented anew and Improved Spark-Plug, of

Y which the following is av full,y clear, and exact description. l j

The present invention relates to new and useful improvements in spark plugs, and it pertains more particularly to that type of spark plug described in an application for Letters Patent filed by me June 30, 1919, bearing Serial No. 307 ,667 and allowed February 20, 1920.

It is one of the primary objects of the present invention to provide a new and improved spark plug in which the terminals are movable with respect to one another to prevent the accumulation of soot and carbon thereon.

It is a further object of the invention to construct a device of this character in such a manner that the electrodes are movable with respect to each other by means of the piston of an internal combustion motor with which the present invention is adapted to be used.

With the above and other objects in view, reference is had to the accompanying drawings, in which- Figure 1 is a view in elevation of a spark plug constructed in accordance with the present invention;

Fig. 2 is a longitudinal sectional viewx thereof taken on the line 2 2 of Fig. 1;

Fig. 3 is adetail view of a portion of the spark plug; l

Fig. 4 is a bottom plan view of the plug;

Fig. 5 is a sectional view taken on the line 5 5 of Fig. l;

Fig. 6 is a detail top plan `view of the guide washer.

Referring more particularly to the drawings, the reference character 6 designates the shell of the spark plug, screw-threaded as at 6 to provide for its attachment in operative osition, and 7 designates the core thereof. ghe shell is formed on its inner surface with a seat or shoulder 8, and the core which is preferably formed of, porcelain, is provided with an annular shoulder 9 adapted to engage the seat 8. Interposed between the shoulder 9 and the seat 8, is a gasket or the vlike 10 preferably formed of metal, said gasket serving to form a gas-tight joint between the shell 6 and core 7. For securing vSpeoication of Letters Patent.

Patented Aug. 2, 1921.

the core 7 within the shell 6, a nut ll is provided, and said nut is adapted for threaded engagement with the interior of the shell as shown at 12. .The nut l1 is'adapted for engagement with the upper face 13 of the shoulder or enlarglement 9, and interposed with relation to t e nut 11and the upper face of the shoulder 9, is a gasket 14. To secure the nut 11 against movement within the shell 6, a set screw or similar device 15 1s employed, the set screw passing through the shell into engagement with the nut 11.

The core 7 is provided with a central passage l6, and at each end of the core, this passage 1s enlarged as 'shown at 17 and 18, respectively. Mounted in the passage 16 is a rod 20, the lower end thereof being formed with a bifurcated extremity lying in a plane at right angles to the rod, as shown at 21, thus forming a movable electrode. Adjacent the. lower end of the rod 20, it is provided with a piston 22 of a diameter equal to the inner diameter of the enlarged portion 17 of the passage 16. As shown in Fig. 2, the upper wall of the enlarged portion 17 of the central vpassage 16 is angularly arranged, as is also the top of the piston 22. By this construction as as-tight joint betweenl the piston 22 and t e centraly passage 16 is obtained when under compression and during combustion of gas in the cylinder of the motor.

Mounted upon the upper end of the core 7, is ametallic washer or the like 25, and said washer 25 is provided with two recesses 26, the purpose of which will be hereinafter more specifically described.

Rigidly but adjustably secured to the upper end of the rod 20, is a cross arm 27 and said cross arm carries two depending rigid elements 28 adapted for sliding engagement in said recesses 26 to hold the bifurcated electrode 21 in line with the electrode 42. Interposed between the cross head 27 and the bottom wall of the enlar ed portion 18 of the central passage 16, through the core, is a coil spring 30 which tends to normally retain the tapered upper end of the piston in en agement with the angular upper -end of te enlarged portion 17.

In Fig. 3 is shown a poke 35 adapted to embrace the upper end o the core, and each of the legs 36 of the yoke 35 are notched as at 37, for the reception of a band 38, by means of which the yoke is secured in place. The legs 36 of the yoke are adapted to be metricall vThe ban received within cut-out channels 39 at diaopposite points in the core 7. 38 ies in an annular channel in said core and has its free endssecured together by means of a bolt or the like' 40. The legs of the yoke 36 are fastened to the metal washer punched in the sides of the metal washer 25 to hold the legs of the yoke 36 in correct position.

Projecting upwardly from the yoke 35 is a terminal or conductor attaching stem 41,

and said stem carries two nuts 43, by means v angular end of the electrode 42, Fig. 1, re-

moving all deposit of foreign matter. therefrom. As the piston in the motor moves on its compression stroke, the piston 22 is moved to the position shown in Fig. 2, in

which positionthere is suicient gap to give y passing through recesses provided in the metal washer 25 and center! naamw the necessary spark to 'te the charge compressed. As the operatlon of the motor conf tinues, the above action takes place upon each reciprocation of the iston, thus assuring clean electrodes at a times. f

What is claimed is:

1. Ina spark p1 a shell, a hollow core, a stationary electrlo a washerV provided with perforations an carried by said hollow core, and means carried by said movable electrode and movable in the perforations of the washer to guide the movable electrode. 2. In a spark plug, a lshell,'a core, a stationary electrode carried by the shell, a movable electrode carried by the core, means for guiding said movable electrode, a yoke em- -bracing said core, and meansl for securing said oke in position on said core.

3. n a spark plug, a shell, a core, astationary electrode carried by said shell, a movable electrode, a cross-head for. guiding and limiting'the stroke of said movable electrode, a yoke embracing said core, and means for securing said yoke in place on said core.

JAMES STEPHEN COYLE.

e, a movable electrode 

